mellin



(No Model.)

' C. J. MELLIN.

GDMPOUND ENGINE.

10.536,640. Patented Aprlv 2; 1895.

NVENT F\` WITNESSES- UNITED STATES l PATENT OFFICE.

CARL J. MELLIN, OF RICHMOND, VIRGNIA, ASSIGNOR TO THE RICHMOND LOCOMOTIVE AND MACHINE WORKS, OF SAME PLACE.

COMPOUND ENGINE.

SPECIFICATION forming part of Letters Patent No. 536,640, dated April 2, 1895.-

Application filed April 1l, 1894.

To aZZZ whom it may concern: Be it known that I, CARL J MELLIN, a citizen of the United States, and a resident of pound engine at starting, whereby the valve will be automatically operated for changing from one to the other condition, and pressure will be duly limited in the low pressure cylinder for safety and practicability, as hereinafter described reference being made to the accompanying drawings, in whichv Figure l, is a longitudinal sectional elevation of my improved intercepting valve with the valve open as when working compound. Fig. 2, is a similar section with the parts in the positions as when Working steam direct in both cylinders, and Fig.3,is a similar section with the parts in the positions as when working steam direct in both cylinders, and with the live steam admission valve closed by overbalancing pressure in the low pressure cylinder to prevent excessive pressure therein. The valve casel a, is to be connected at any suitable position in the passage for the exhaust steam from the high pressure cylinder to the low pressure cylinder so that the steam is received in the chamber b, between which and the outlet c to the low pressure cylinder is theY intercepting valve Z arranged to be opened automatically by the pressure in receiver b for the flow of the steam into the low pressure cylinder when working in the compound system. On the back of this valve CZ is a hollow stem or sleeve etted to slide in the bored cylinder fto which live steam is admitted at g from the pipe h always open to live steam when the throttle valve is open, said sleeve e, having a shoulder Z that is subject to live steam pressure for closing valvecZ, the rest of the ysleeve e and the corresponding part f of the sleeve cylinder being of smaller size to enable the steam to have impelling eect on the shoulder. The outer end of the smaller part of the sleeve is open tothe atmosphere.

Serial No. 507,196. (No model.)

At la are ports so placed that they communicate with the steam space g, when valve cZ is closed and admit live steam to the interior of the sleeve. At Z, are other ports in said sleeve so placed that they open communication with the low pressure cylinder at the extremity of sleeve cylinder f, when said valvecZ is closed, and between these ports la and Z, is a piston valve m, which has a seat at n, and closes communication between said/ports to shut ed live steam when pressure rises too high in the low pressure cylinder, said valve being then overbalanced by the cylinder pressure on its other end having communication therewith through other ports o, of said sleeve, so that this valve automatically controls the pressure of live steam in the low pressure cylinder. The stem p, of this valve extends out through part e of the sleeve and has a nut q, between which and the end of the sleeve a coiled spring may be applied to graduate the action of the valve. It will be seen that through this provision of separate means for closing the valve d, and

'for admission of the steam each may be better adapted as to area of steam space for its particular purpose, whereby less area being required on shoulder t' for closing the valve CZ only, than if for admission of the steam that way also, the said valve will close more `gently and with less damage by hammering the seat. The valve d closes in a recess CZ the depth of which is to be such that the said valve enters the mouth of the recess at the moment ports Z open at the end of cylinder f, and thus prevents escape of live steam into the receiver during the rest of the movement of valve d, in closing. ,The sleeve e e is made separately from valve d and is bolted thereto.

At s, I represent the cylinder, and at t, the piston of the dash-pot employed to check the closing of the valve CZ, and for exhausting receiver b, when the valve d is closed, and live steam is to be used directly in both steam cylinders, the ports u opening said exhaust after passing the head of the piston, but this is the subject of claims in another application for a patent and is not claimed herein. h

When the engine is running the pressure of exhaust steam in the receiver on valve Z overbalances the pressure of live steam on shoulder ."Z, and opens said valve. The engine IOO then works by the compound system, but when there is little or no pressure of exhaust steam in the receiver, the live steam pressure 'on shoulder t'closes valve d, and opens admission for live steam through openings 7c to the reducing valve m, which in turn opens and admits live steam to the low pressure cylinder. Then both cylinders work with live steam.

The hollow stem e, e of the intercepting valve is bored in three different sizes. The piston m of the live steam admission and reducing valve is arranged in the larger portion of the bore and closes on the seat n, which is intermediate of the ports k, Z, and is a ground joint for tight closing. The portion of the bore of said sleeve and the shoulder z together with the intermediate sectionp of the stem of valve rm, determines the amount of reduction of the live steam admitted, and the ratio between the smallest and the largest bores determines the steam pressure in the low pressure cylinder in running with live steam direct in both cylinders. The inter mediate bore in the live steam passage to the low pressure cylinder, in which the intermediate portion p of the reducing valve stem tits being reduced to the smallest practicable limits, affords sufficiently large area for the steam in a bore of comparatively small size.

The shoulder t on which the live steam acts to close the intercepting valve never passes out of the end of the cylinderf, and conse quently there is no other admission for live steam except through the reducing valve. When the intercepting valve is open, piston valve m passes ports l to its seat, and shoulder t' passes ports 7a to its seat j, and the live steam ports 7s are shifted past shoulder j into the smallest part of the bore of cylindcrf thus shutting oit the supply of live steam to the reducing valve, so that the reducing Valve being closed by receiver pressure, the live steam and the steam from the receiver are eiectually shut off by ground valve seats, the former by the shoulder i of the hollow stem of the intercepting valve and the latter by the shoulder of the reducing valve.

I claim- 1. In a compound engine, the combination with the intercepting valve in the steam receiver between the high and low pressure cylinders, of the sleeve having the exterior shoulder subject to live steam for closing the valve, and the admission ports for the live steam to the low pressure cylinder through the sleeve, said valve adapted to cut 0E communication between the high and low pressure sides of the receiver at or before the opening of said live steam admission ports substantially as described.

2. In a compound engine, the combination with the intercepting valve in the steam relow pressure cylinder; and the valveV in said sleeve subject to overbalancing effect of excessive pressure in the low pressure cylinder to automatically shut olf the live steam substantiall y as described.

3. In a compound engine, the combination with the intercepting valvein the steam receiver between the high and low pressure cylinders, of the sleeve having the shoulder subject to liveV steam for closing the valve, and the admission ports for the live stealn to the low pressure cylinder; and the valve in said sleeve to shut off the live steam, said sleeve also having the ports behind said valve and said valve adapted to be over-balanced by excessive pressure thereto admitted behind it, and to thereby automatically shut off the live steam substantially as described.

4. The combination with the hollow stem of the intercepting valve having the differential bores of the extremities, the steam ports c, Z, and the seat n, intermediate of said ports, ot' the red ucing valve having the small and larger extremities, and theintermediate connecting stem, substantially as described.

5. The combination with the hollow stem of the intercepting valve having the differential bores of the extremities and intermediate portion, the steam ports 7c, Z, and the seat n, intermediate of said ports, of the reducing valve having the small and large extremities and the intermediate connecting Vstem sub stantially as described. j

6. The combination with the hollow stein, of the intercepting valve having the shoulder t', the ports 7c and Z, and o, and shoulder n; of the cylinderf having the steam space g, and

3the seatj, and the reducing valve having the larger and smaller extremities, and adapted `to close on the seat n, substantially as described.

7. The combination with the intercepting valve, of the hollow stem of said valve having the ports k, Z; the cylinderf for said stem having the steam space g and seatj, and the reducing valve located in said stem, said sleeve and cylinder adapted for the ports 7c to cut o the steam space, and the reducing valve adapted to cut o ports Z, when the intercepting valve opens substantially as described.

Signed at Richmond, in the county of I-Ienrico and Stateof Virginia, this 4th day of April, A. D. 1894.

CARL J. MELLIN. Witnesses: j

L. P. RoUN,

D. C. BARRAUD.

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